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Old 02-03-2006, 12:18 AM   #41
jojoe cute
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Still waiting for some bro. help to calculate....
See how low it can cold....

Wah yr room so warm ah? U keeping wat shrimp...


Quote:
Originally Posted by Arrowana17
so how? managed to achieve????....if successful, can help me to diy? pls....

coz my room temperature is abt 31 to 32 degree celsius
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Old 02-03-2006, 01:11 AM   #42
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Quote:
Originally Posted by silane
For calculation, 38W of cooling power is used, that is a reasonable expectation of cooling power from a 75W peltier.

It is expected to cool a standard 1.5 tank from ambient 30C to 27.3C, with 100% of the time running at electrical power of 75W.

It is expected to cool a standard 1.5 tank from ambient 29C to 26.3C, with 100% of the time running at electrical power of 75W.

It is expected to cool a standard 1.5 tank from ambient 29C to 26.6C with 5W of heat introduced by lamp and filter, with 100% of the time running at electrical power of 75W.

Above calculation is done with assumption that the heatsink and fan assembly can handle the heat sufficiently.

Qc = C x m x dT

c = 4816 J / kg
m= 40
dt = 4 degrees C ( asumming ambient of 28C cooled to 24C)

Qc is heatload of your tank. From software simulation , joe's 40L tank's heatload is 68.67W. You need a TEM with Qc of at least 69W for ideal situation. would recommend you get a TEM with Qc of at least 90W. Your 75W Tem only has Qc(max) of around 40W .


cheers
xtrekker

Last edited by xtrekker; 02-03-2006 at 01:17 AM.
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Old 02-03-2006, 02:07 AM   #43
silane
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Quote:
Originally Posted by xtrekker
Qc = C x m x dT

c = 4816 J / kg
m= 40
dt = 4 degrees C ( asumming ambient of 28C cooled to 24C)

Qc is heatload of your tank. From software simulation , joe's 40L tank's heatload is 68.67W. You need a TEM with Qc of at least 69W for ideal situation. would recommend you get a TEM with Qc of at least 90W. Your 75W Tem only has Qc(max) of around 40W .


cheers
xtrekker

Thank for the validation, we are close.
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Old 02-03-2006, 02:12 AM   #44
karen33
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Quote:
Originally Posted by silane
This is my DIY integrated chiller into a 1 feet tank, able to achieve down to 22C and temperature can be regulated at higher then 22C, I am running it at 24/25C for good.

Checking the performance, it can achieve 22C even with an internal filter to circulate the water and to introduce heat as in normal operation



Showing the cold fin with maximum exposure to the water.


It is much cheaper to DIY then to buy such a microchiller.
Your DIY skill is good!
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Old 02-03-2006, 08:56 AM   #45
Arrowana17
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dun noe wat shrimp....i bought frm the previous owner the entire set up...so far....1 yellow goby n 1 clownfish n 1 damsel die liaoz...i tink becoz of the heat n water condition...
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Old 02-03-2006, 11:58 AM   #46
jojoe cute
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Thanks bro....

Silane & xtrekker, for the calculation...

So it may only work on 1.5Ft tank size & below...

I put balck sticker on heatsink, so lit look nicer..
Wonder the sticker will melt off anot le...

Last edited by jojoe cute; 10-06-2006 at 10:50 PM.
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Old 02-03-2006, 12:24 PM   #47
byfun
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Quote:
Originally Posted by jojoe cute
Thanks bro....

Silane & xtrekker, for the calculation...

So it may only work on 1.5Ft tank size & below...

I put balck sticker on heatsink, so lit look nicer..
Wonder the sticker will melt off anot le...
Nothing beat an experiment Just get a small pail with water and try it out. That's what i did last time.
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Old 02-03-2006, 01:49 PM   #48
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Its beyond any reasonable doubts that it looks better in black .Dun forget that sticking a sticker is like sticking a thin layer of insulation to your heatsink. The purpose of heatsink is to dissipate heat. Not insulate. If want to look good , and increase the heat dissipation of your heat sink i suggest that you should anodised your heatsink.

It might work but if any conditions change yours do not have to power to overcome it . just like a sampan it will be smooth sailing on clam sea but can it cope with a storm? Well , nothing in this world can work till you try it out.

The calucation is a simplified version its just provide a rough guide for chosing a TEM. Those ppl taking thermodyamics will be laught at it. Calculating the Qc is complex with alot of realtime variablies.

To help you understand better there are a few assumptions i made :

1. Your ambient temp is at 27C and its at steady state ie remains constant throughtout the entire operation.

2. There are no other heat input except from your 5mm glass of tank is taking in heat at 0.8w/m/k , active heatload (filter pump ) is at 10W. things exculded is radiation heat from your lighting , any warm blooded occupants in your tank , etc

3. Conditions are assumed steady-state (do not change with time) ie constant external conditions, constant internal temperature

4. Ideal coupling of your cold plate to TEM to heatsink. That is the heat would flow "smoothly" from your tank to heatsink without any thermal resistance , junction to junction resistance.

I might be wrong. Anyone pls point out any mistake or assumptions i made.

cheers
xtrekker.
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Old 02-03-2006, 03:56 PM   #49
silane
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Quote:
Originally Posted by xtrekker
Its beyond any reasonable doubts that it looks better in black .Dun forget that sticking a sticker is like sticking a thin layer of insulation to your heatsink. The purpose of heatsink is to dissipate heat. Not insulate. If want to look good , and increase the heat dissipation of your heat sink i suggest that you should anodised your heatsink.

It might work but if any conditions change yours do not have to power to overcome it . just like a sampan it will be smooth sailing on clam sea but can it cope with a storm? Well , nothing in this world can work till you try it out.

The calucation is a simplified version its just provide a rough guide for chosing a TEM. Those ppl taking thermodyamics will be laught at it. Calculating the Qc is complex with alot of realtime variablies.

To help you understand better there are a few assumptions i made :

1. Your ambient temp is at 27C and its at steady state ie remains constant throughtout the entire operation.

2. There are no other heat input except from your 5mm glass of tank is taking in heat at 0.8w/m/k , active heatload (filter pump ) is at 10W. things exculded is radiation heat from your lighting , any warm blooded occupants in your tank , etc

3. Conditions are assumed steady-state (do not change with time) ie constant external conditions, constant internal temperature

4. Ideal coupling of your cold plate to TEM to heatsink. That is the heat would flow "smoothly" from your tank to heatsink without any thermal resistance , junction to junction resistance.

I might be wrong. Anyone pls point out any mistake or assumptions i made.

cheers
xtrekker.

I am overwhelmed by the info. One more sink to ambient thermal resistance also play a part too, which need to be small enough to handle the heat.
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Old 02-03-2006, 04:02 PM   #50
silane
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Quote:
Originally Posted by karen33
Your DIY skill is good!

Thank, Karen.
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